Thanks to Ess Fourty for the detailed pictures on how to adjust the lean on the carb.  

I went 1/2 turn CCW and that cured 90% of the backfire, but when I took it out to test, I still had one big backfire after I cranked down on it and then let off the throttle.  Should I go another 1/2 turn, or what should I do?

I checked the header bolts and tightened them down just to make sure. I also put my hand in front and revved the engine up and didn't feel any air.

PS The weather in SE Alaska still sucks.  It is 40 degrees and snowing off and on.  When I went for a little test spin, it started snowing and hailing on me.  What's a guy to do?  Mother Nature is a b%tch.

The last little bit of carb mixture may take some fiddle'n with 1/8 turns - but a little leak at either place can sure make it pop - let's it such raw air into the exhaust - at the muffler/head pipe and at the head it self - the gasket at the head/header flang is a coated crush gasket - after it's been fully crushed and the coating is gone it's pretty tough to get a perfect seal - easy enough to replace.